The main patron saint of Trecastagni is Saint Nicholas of Bari, celebrated on 10 May together with the co-patrons, the martyr saints Alfio, Filadelfo and Cirino. The sanctuary of the three martyr saints became a destination for particularly numerous pilgrimages precisely in the month of May, on the occasion of their feast: inside the sanctuary a collection of votive offerings is kept, testimony to the spread of their cult and of pilgrimages to the town.
Among the town's main cultural events is also the Festa del Castagno, dedicated to promoting local typical products and in particular chestnut-related production; since 1999 the Trecastagni International Blues Festival has also been held. The town preserves numerous other historic churches, including those of San Nicolò di Bari, Santa Maria della Misericordia and Santa Maria dell'Aiuto.
